ð¥ å
§ç§å°ç§èåç
Mechanistic Deep Dive
T-Cell Activation
- Signal 1: TCR + MHC + peptide
- Signal 2: CD28 + B7 (CTLA-4 Ig blocks this â belatacept)
- Signal 3: cytokines (IL-2, others)
- All three needed for activation
Calcineurin Inhibitor Mechanism
- Tacrolimus + FKBP-12 â inhibits calcineurin â â NFAT â â IL-2 â â T-cell activation
- Cyclosporine + cyclophilin â same downstream effect
- Side effects: â renal blood flow â CNI nephrotoxicity (afferent vasoconstriction)
MMF Mechanism
- Inhibits inosine monophosphate dehydrogenase (IMPDH)
- B + T cell proliferation
- Lymphocyte-specific
mTOR Inhibitor Mechanism
- Inhibits mTOR signaling
- Cell cycle arrest
- Effects on T cells, fibroblasts
- Side effects: hyperlipidemia, edema, mouth ulcers
Belatacept Mechanism
- Co-stimulation blockade
- Prevents T-cell activation
- CNI-sparing
Recent Trials & Updates
Xenotransplantation (Pig Kidney 2023-2024)
- First human pig kidney transplants
- Multiple gene edits (alpha-Gal, GHR, CMAH, etc.)
- Limited duration
- Future direction with iterative improvements
Tegoprubart (Anti-CD40L) Trials
- Co-stimulation blockade
- Phase 2 trials
- Future alternative
Bedside Decision Algorithms
- AI for rejection prediction
- ctDNA + dd-cfDNA monitoring
- Personalized immunosuppression
dd-cfDNA (Donor-Derived Cell-Free DNA)
- AlloSure, Prospera
- Detect rejection earlier
- Less invasive than biopsy
- Emerging clinical use
BENEFIT-EXT (2017, 2020) â Belatacept Long-Term
- Better graft survival vs cyclosporine
- Better GFR preserved
- Higher acute rejection initially
KOLT Outcomes
- Korean Organ Transplant data
Iscalimab (Anti-CD40)
- Phase 2 trials
- Co-stim blockade
High-Yield Specialist Points
Sensitization Management
- Desensitization: plasmapheresis + IVIG + rituximab + sometimes proteasome inhibitor
- IdeS (imlifidase) â single-dose
- Approved in Europe + USA for transplant
Kidney Paired Donation (KPD)
- Network exchanges
- Incompatible pairs match through swaps
- Expanded transplant access
Recurrence of FSGS Primary
- 20-30% recurrence
- Plasmapheresis pre-transplant (limited evidence)
- ICZ Apheresis or RIT for severe recurrence
Anti-PLA2R + MN
- Recurrent MN risk
- Monitor levels
- Anti-CD20 (rituximab) for recurrence
EBV-Negative Recipient
- Higher PTLD risk
- Less belatacept (EBV-naive)
- Monitor EBV PCR
- Prophylactic valganciclovir + acyclovir
CMV Tissue Invasive Disease
- Treatment: ganciclovir IV 5 mg/kg q12h à 2-3 weeks â valganciclovir oral
- Resistance: foscarnet, cidofovir, maribavir (new for refractory)
- Letermovir prophylaxis (allotransplant primarily)
BK Virus Nephropathy
- Plasma BK > 10,000 copies/mL
- Renal biopsy: tubular epithelial cells with viral inclusions, T-cell infiltrate
- Reduction of IS first-line
- Cidofovir, IVIG for severe (limited)
Tacrolimus Drug Interactions
- â Levels: azoles (fluconazole, voriconazole), macrolides (clarithromycin), CCBs (diltiazem), grapefruit
- â Levels: rifampin, phenytoin, carbamazepine, St Johnâs wort
- Therapeutic drug monitoring essential
Pregnancy After Transplant
- Best after 1-2 years stable function
- Cr < 1.5
- BP controlled
- IS adjustment: avoid MMF (teratogenic), can use azathioprine
- Multidisciplinary management
Re-Transplant
- For first allograft loss
- More sensitized typically
- Increased PRA management
- Outcomes acceptable
Conservative Care
- Failed transplant
- High risk for re-transplant
- Discussion of dialysis vs continued conservative
Living Donor Long-Term
- Most maintain renal function
- Small â ESKD risk (long-term studies)
- BP, kidney function follow-up
- Pregnancy increased risk (slight)
Pearls
- Transplant best for ESKD (vs dialysis)
- LD > DD outcomes
- Maintenance: tacrolimus + MMF + prednisone
- Induction: basiliximab (low-risk) or rATG (high-risk)
- Belatacept: CNI-sparing; EBV+ only
- PTLD: EBV-driven; reduce IS + rituximab
- CMV: valganciclovir prophylaxis 6-12 mo
- BK nephropathy: reduce IS
- Skin cancer: SCC > BCC
- dd-cfDNA: emerging non-invasive marker
- Xenotransplantation (pig kidney) 2023-2024 first human attempts